This study, involving 215 students and 63 teachers, addressed three concerns related to mainstreaming for hearing imparied students: the selection process, the difference between a mainstream placement with an interpreter and a self-contained placement, and the quality of the educational experience. Almost half of the variance in achievement between the two settings is described. Three conclusions can be drawn. First, student background factors are a primary determinant of achievement. Second, mainstreaming with an interpreter has no specific effect on achievement for hearing impaired students. Third, the quality of instruction is the prime determinant of achievement, regardless of placement.